A new poll commissioned by the Sierra Club has found strong support for clean and renewable energy among Connecticut voters across the political spectrum.

The survey of 500 likely voters was conducted in July by Washington D.C. Democratic polling firm Greenberg Quinlan Rosner Research (GQRR), and could be the most comprehensive look in years at how Connecticut residents think about energy policies.

It found that 73 percent of voters support moving Connecticut over the coming decade to 100 percent renewable energy, such as solar and wind. That includes 88 percent of Democrats, 71 percent of independents and 54 percent of Republicans. Meantime, 72 percent of voters said climate change is a serious problem, while 65 percent want state government to increase the amount of money it spends on clean energy.

Thus far, gubernatorial candidates in Connecticut have been focused on discussing tax and spending policies, while talks about energy issues have been minimal. But the poll suggests that politicians' stances on energy will be a factor at the ballot box, according to the Sierra Club.

Sixty-percent of voters said they were more likely to vote for a candidate who supports the state moving toward a goal of 100 percent renewable energy, including 82 percent of Democrat respondents, 57 percent of independents and 36 percent of Republicans.

"I don't know if I would say it's surprising, but it's quite a robust group of voters, and it extends across party lines," said Ben Winston, senior associate at GQRR.

While nearly three-quarters of respondents support a move to 100 percent renewable energy by 2030, which Winston conceded is "a fairly ambitious goal," it's unclear how many understood what that might entail or cost.

The amount of clean energy used in Connecticut is measured by a requirement known as the Renewable Portfolio Standard (RPS), which dictates what percentage of electricity sold by the state's utility companies must come from renewable sources, as defined by state law. Renewable energy costs more money than regular fossil-fuel-generated power.

The Department of Energy and Environmental Protection (DEEP) estimated earlier this year that the state's current RPS requirement, which mandates utilities to source 17 percent of their electricity from renewable sources, costs ratepayers $250 million per year above what it would cost to produce the same amount of energy from fossil fuels. That annual cost will rise to around $300 million in the early 2020s, before gradually declining to $200 million by 2030, DEEP has projected. However, the estimates did not factor in a new state law that doubled down on the state's clean energy mandates, requiring that utilities source 40 percent of their electricity from renewables by 2030.

The law is expected to increase ratepayer costs, but by how much will depend on many factors, such as whether renewable technology continues to decline in cost, as it has in recent years.

There's also debate over the logistics of moving toward 100 percent renewables, which would likely require major investments in high-voltage electric grid infrastructure.